In applications such as driving a discharge laser or a pulsed radar, there is a need for producing short, high energy pulses at a high repetition rate. For example, a driver for a copper vapor laser or a CO.sub.2 laser may require pulses of approximately 1 joule or greater, of approximately 10-20 nanoseconds duration and having rise times of 1 nanosecond or less. Such lasers may be utilized in uranium isotope separation and in a broad spectrum of other research, industrial, government and other applications. One high voltage pulsed power source suitable for use in such applications is shown in HIGH VOLTAGE PULSE POWER SOURCE, U.S. patent application ser. no. 07/778,313, filed Oct. 16, 1991 and incorporated herein by reference.
As noted therein, earlier thyratron-based pulse drivers were limited by the performance of the thyratron. One important limitation on thyratron performance is speed. Thyratrons do not have a fast enough rise time to provide multiple-joule pulses having durations in a range of several nanoseconds. Likewise, even the high voltage pulse power source of the U.S. patent application ser. no. 07/778,313 referenced above does not produce pulse rise times in the range of several nanoseconds or shorter.
A pulse rise time may be reduced by passing a pulse through an electromaqnetic shock line. A discussion of the general theory of electromagnetic shock lines is provided in Electromaqnetic Shock Waves, by D. G. Katayev, originally published in the U.S.S.R. by Sovietskaye Radio, Moscow, 1963. An English edition was first published by Iliffe Books, Ltd., London, 1966. The shock lines described therein are capable of operating in the 1/2 MW power range on only 2-3 nS output pulses. However, the power-handling capability of these lines, the output pulse rise time, and the power dissipation in these lines is unsatisfactory for current applications.
It is a general aim of the present invention to produce high power pulses in the nanosecond duration range or shorter, having high energy contents.
Another general aim of the present invention is to provide an apparatus capable of reducing the rise time of high power pulses in the nanosecond duration range from several nanoseconds to hundreds of picoseconds, without a significant loss of power.